/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package com.badlogic.gdx.physics.box2d;

import com.badlogic.gdx.math.Vector2;

/**
 * The class manages contact between two shapes. A contact exists for each overlapping AABB in the broad-phase (except if
 * filtered). Therefore a contact object may exist that has no contact points.
 * @author mzechner
 * 
 */
public class Contact {
	/** the address **/
	protected long addr;

	/** the world **/
	protected World world;

	/** the world manifold **/
	protected final WorldManifold worldManifold = new WorldManifold();

	protected Contact (World world, long addr) {
		this.addr = addr;
		this.world = world;
	}

	/**
	 * Get the world manifold.
	 */
	private final float[] tmp = new float[6];

	public WorldManifold getWorldManifold () {
		int numContactPoints = jniGetWorldManifold(addr, tmp);

		worldManifold.numContactPoints = numContactPoints;
		worldManifold.normal.set(tmp[0], tmp[1]);
		for (int i = 0; i < numContactPoints; i++) {
			Vector2 point = worldManifold.points[i];
			point.x = tmp[2 + i * 2];
			point.y = tmp[2 + i * 2 + 1];
		}

		return worldManifold;
	}

	private native int jniGetWorldManifold (long addr, float[] manifold);

	public boolean isTouching () {
		return jniIsTouching(addr);
	}

	private native boolean jniIsTouching (long addr);

	/**
	 * Enable/disable this contact. This can be used inside the pre-solve contact listener. The contact is only disabled for the
	 * current time step (or sub-step in continuous collisions).
	 */
	public void setEnabled (boolean flag) {
		jniSetEnabled(addr, flag);
	}

	private native void jniSetEnabled (long addr, boolean flag);

	/**
	 * Has this contact been disabled?
	 */
	public boolean isEnabled () {
		return jniIsEnabled(addr);
	}

	private native boolean jniIsEnabled (long addr);

	/**
	 * Get the first fixture in this contact.
	 */
	public Fixture getFixtureA () {
		return world.fixtures.get(jniGetFixtureA(addr));
	}

	private native long jniGetFixtureA (long addr);

	/**
	 * Get the second fixture in this contact.
	 */
	public Fixture getFixtureB () {
		return world.fixtures.get(jniGetFixtureB(addr));
	}

	private native long jniGetFixtureB (long addr);
}